1. Field of the Invention
The present invention relates to a character drawing apparatus for use in combination with various information display to draw a character pattern represented by a character code or a character code string.
2. Description of the Prior Art
Character drawing apparatus are classified roughly into dot type character drawing apparatus which store and reproduce character patterns in dot patterns, and vector type character drawing apparatus which store character patterns in vector data and convert the vector data into dot patterns in reproducing characters. A vector type character drawing apparatus, such as a character pattern generator disclosed in Japanese Patent Laid-open (Kokai) No. 62-251983, stores a character in vector data representing the character outline and reproduces the character in a high quality by solidifying the space enclosed by the character outline. Storing a character pattern in vector data has an advantage that the character pattern can easily be enlarged or reduced. Researches have been made to develop a method of drawing a character pattern written with a writing brush (hereinafter referred to as "brush-written character pattern") by a computer by writing a brush-written character along the strokes. Such a method is disclosed in "Generation of Brush-written Chinese Characters by Computer", Denshi Tsushin Gakkai Ronbun-shi, Vol. J-67-D, No. 5, pp. 599-606, May, 1984.
A conventional vector type character drawing apparatus disclosed in Japanese Patent Laid-open (Kokai) No. 62-251983 will be described hereinafter by way of example. Referring to FIG. 71 the vector type character drawing apparatus comprises a stroke memory 181 storing stroke data corresponding to character codes, a stroke drawing operation control unit 182 for converting stroke data read from the stroke memory 181 into a corresponding dot pattern, a dot pattern memory 183 for storing the dot pattern produced by the stroke drawing control unit 182, a solidification control unit 184 for solidifying a closed region enclosed by the character outline of the character pattern read from the dot pattern memory 183, and a main control unit 185 for controlling the general operation of the character drawing apparatus.
The operation of the character drawing apparatus will be described hereinafter. FIG. 72 is an illustration of assistance in explaining exemplary stroke data for the case of the letter J by way of example. When a character code representing the letter J is entered by an external device into the character drawing apparatus, a series of stroke data 121 to 130 of the letter J is read from the stroke memory 181 and the stroke data 121 to 130 are transferred to the stroke drawing control unit 182. Then, the stroke drawing operation control unit 182 writes dots at points in the dot pattern memory 183 respectively corresponding to the stroke data 121 to 130. After the dot patterns of all the stroke data 121 to 130 have been drawn on the dot pattern memory 183, the character outline of the letter J as shown in FIG. 72 is loaded into the dot pattern memory 183. Then, the solidification control unit 184 reads the character outline of the character pattern of the letter J from the dot pattern memory 183 and solidifies a region enclosed by the character outline to provide a dot character output. These steps are controlled sequentially by the main control unit 185. Storage of a character pattern in vectors representing the strokes of the character pattern facilitates enlargement and reduction of the character pattern.
The conventional character drawing apparatus thus constructed draws a character only on the bases of the character drawing data representing the morphology of the character, the character drawing apparatus is unable to control a time interval necessary for drawing a character. A vector type character drawing apparatus draws the character outline of a character first, and then solidifies a closed region enclosed by the character outline to draw the character, and the outline drawing speed and the closed region solidifying speed are dependent on the processing algorithm and drawing speed of the character drawing unit. On the other hand, the dot type character drawing apparatus scans the dot pattern stored in the memory and transfers the dot pattern to the image memory to draw the corresponding character. Accordingly, the character is displayed gradually on the display in order of scanning cycles, and the displaying speed is dependent on the data transfer speed of the character drawing unit.
Therefore, stroke speed is different from that of handwriting and the drawing point shifts to the starting position of the next stroke and the drawing point starts drawing the next stroke immediately after the completion of a stroke. Since the speed and timing of drawing are considerably different from those of handwriting, the conventional character drawing apparatus makes a person observing the drawing process disagreeable.
It is effective for making a person interested in a character string displayed on the display and for making the person understand correctly the information expressed by the character string to display the characters of the character string in a mode resembling that of handwriting. For example, a time interval allowed to the person for concentrating attention on a character string to be emphasized will be extended and hence the information expressed by the character string will surely remain in his memory if the characters of the character string are drawn slowly. In handwriting a character string, a short time interval is required to move the point of the pen from the end point of the last stroke of a character to the starting point of the first stroke of the next character. This short time interval allows the person to shift the visual point from the preceding character position to the succeeding character position, so that the person is able to read the character string easily and is able to concentrate attention on reading the character string. However, drawing time cannot intentionally be varied because the conventional character drawing apparatus is unable to control drawing time, and the conventional character drawing apparatus is unable to display character strings so that character strings can readily be recognized.